dnn-layer-math-unary-test: add unit test for tanh

Signed-off-by: Ting Fu <ting.fu@intel.com>

tests/dnn/dnn-layer-mathunary-test.c

@@ -48,6 +48,8 @@ static float get_expected(float f, DNNMathUnaryOperation op)
         return sinh(f);
     case DMUO_COSH:
         return cosh(f);
+    case DMUO_TANH:
+        return tanh(f);
     default:
         av_assert0(!"not supported yet");
         return 0.f;
@@ -109,5 +111,7 @@ int main(int agrc, char **argv)
         return 1;
     if (test(DMUO_COSH))
         return 1;
+    if (test(DMUO_TANH))
+        return 1;
     return 0;
 }